All spell casters gain their abilities through a form of demon possession. So in order to gain magical abilites, PCs must track down and trap demons. Of course there are some pretty powerful demons, if the demon is stronger than the PC, the PC could find themselves subjugated to the Demon's will.
Patterns in surnames: There are many ways a surname could have evolved over centuries. One possibility is migration. A Roman name may have traveled to France and hence to England where it was later Anglicized. Case in point - the surname Lawrence went from Laurentius (Roman) to Laurent (French) to Lawrence (English) and then to Lowry (Scottish). There is also natural etymological evolution. For example, a Middle English spelling may have evolved to a modern English spelling (e.g. Stiward to Stewart). Where did your character's Surname come from?